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  #11  
Old 2006-11-30, 02:00
dwoodruff dwoodruff is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Viktor,

Quote:
During the broken synchronization, the server sends all OX folders as DataStores inside the DevInf which was requested by the client.
When I look at the ssldump.Private_Contacts, I see the DevInf12 that requests Private/Contacts. You send previously that all the folders are sent because the client requests it. Can you explain more where you see this request for all folders?

Also, according to the tomcat logs, the client only requests Private/Contacts. See attached tomcat logs for:
2006-11-22 19:17:29 StandardContext[/syncml]Receiving Alert (201) for "Private/Contacts"

I don't see where it is asking for calendar and/or task info, even though it is being sent by OX.

Can you verify that the client is asking for contacts, calendar, and tasks based on the logs I've sent? Or do you need additional info?

Lukas -- is the your client asking for all objects as Viktor claimed earlier? If so, why is it doing it if I only have Private/Contacts entered and checked in the client?

We would really like to roll this out to our users but I cannot move forward until I know it will work.

Thanks to both of you!
Donnie
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File Type: zip ssl_problem.zip (27.2 KB, 1 views)
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  #12  
Old 2006-11-30, 12:18
VPracht VPracht is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

The client requests device information from the server:
> 2006-11-22 19:14:49 StandardContext[/syncml]Receiving Get

The device information contains information about all available data stores. SyncML data stores are mapped to OX folders. Therefore, every server device information contains information about all folders.

I don't know why the folder information is missing when the path is "contacts", but if we fix it now, then the folder information would be always sent, and the synchronization would break even with "contacts".

The real problem is not the information about folders, it's the message size. As soon as you have enough data to synchronize, you will encounter the same problem. This is probably the case when you synchronize the tasks and appointments. My suspects right now are the many small fragments at the end of a message in the ssldump log.

An interesting test would be to create a contact with a huge comment over 10 KB and to try to synchronize it.

BTW: the "/syncml/palm" path seems to be not necessary anymore, because it's autodetected from the client's device information:
> 2006-11-22 19:14:49 StandardContext[/syncml]Receiving Put
> 2006-11-22 19:14:49 StandardContext[/syncml]Using Time Zone America/New_York
> 2006-11-22 19:14:49 StandardContext[/syncml]DevInf for ./contacts stored and applied.
> 2006-11-22 19:14:49 StandardContext[/syncml]Path info was not set before.
> Detected a palm device through device information in Results command. Setting path info to "palm"
(I just noticed it because it was directly above the Get command in the log.)
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  #13  
Old 2006-11-30, 18:39
dwoodruff dwoodruff is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Quote:
My suspects right now are the many small fragments at the end of a message in the ssldump log.
Viktor -- so are you saying this is something the client (Synthesis SyncML) is not handling properly? Or is this a problem on the server end?

Lukas -- can you comment on this?

Quote:
An interesting test would be to create a contact with a huge comment over 10 KB and to try to synchronize it.
This causes a similar problem! I've attached some new ssldumps and tomcat log. I sync with one contact and it worked. Then I edited the contact on OX and added a 10KB comment (a bunch of zzzzzzzzz). Now when I sync, I get "No SyncML response" on the client and the "Waiting for Client-Response..." on the server end.

Is this related to the problem with the amount of data flowing to the device? Does this help? Do you need anything else from me?

Thanks for your help!
Donnie
Attached Files
File Type: zip zzzz_problem.zip (14.7 KB, 2 views)

Last edited by dwoodruff; 2006-12-01 at 01:00. Reason: additional info
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  #14  
Old 2006-12-01, 15:22
VPracht VPracht is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Quote:
Viktor -- so are you saying this is something the client (Synthesis SyncML) is not handling properly? Or is this a problem on the server end?
If it's a problem on the server side, I don't see it (which could be expected, as we wrote the code according to our best understanding of the specifications). I'd like a comment from Lukas if he sees anything wrong or unexpected in the packets sent by the server.

If it's not a server problem, in the best case, the client doesn't support chunked HTTP encoding. I'm no Apache expert, but I hope there is some obscure configuration setting which disables chunked encoding. It could also be in Tomcat and/or mod_jk. Disabling chunked encoding would help with localizing the problem.

In the worst case, the problem is somewhere between the server and the client. Since the appearance of the problem depends on low-level things like message size and HTTP vs. HTTPS, it very well could be Tomcat, Apache, your wireless ISP, or the HTTPS implementation in Palm OS. In this case, since neither we nor Synthesis know the code, further debugging would be very... interesting.

At last, there are some not-so-bad news: the little fragments at the end of previous logs seem not to be the problem, because at the end of the new "bad" synchronization log, the client cuts the connection immediately after a big data chunk:

3d 30 41 3d 30 44 3d 0d 0a 7a 7a 7a 7a 7a 7a 7a =0A=0D=..zzzzzzz
---------------------------------------------------------------
1 1164912930.9595 (0.1277) C>S TCP FIN
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  #15  
Old 2006-12-02, 16:44
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luz luz is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Quote:
Originally Posted by VPracht View Post
If it's not a server problem, in the best case, the client doesn't support chunked HTTP encoding.
The client does support chunked HTTP encoding. And it's well tested because when a server uses gzip-compressed messages (which the PRO client supports receiving), it is usually sent as chunked HTTP.

Quote:
In the worst case, the problem is somewhere between the server and the client. Since the appearance of the problem depends on low-level things like message size and HTTP vs. HTTPS, it very well could be Tomcat, Apache, your wireless ISP, or the HTTPS implementation in Palm OS. In this case, since neither we nor Synthesis know the code, further debugging would be very... interesting.
Yes However to narrow down this, I'd recommend doing some tests with the Palm locally connected to the LAN (using softick PPP for example). This would bypass all wireless ISP gateways - a not so uncommon source for problems, because they often use all sorts of "smart" proxy magic which is ususally designed for web browsing, not SyncML.
With the Palm connecting via a local PC to the internet, you could also run WireShark/Ethereal on that PC and log the traffic.
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  #16  
Old 2006-12-03, 22:44
dwoodruff dwoodruff is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Viktor:
Is it possible for you to test the scenario of creating a contact with a comment of 10KB and then sync with the Synthesis 3.0 client on one of your test servers?

I would like to see if this problem also occurs on one of your servers. This would also eliminate the wireless ISP concern.
Lukas:
I'll test the softick ppp option tomorrow and update you. Since the problem only occurs on HTTPS requests, I don't think the wireshark/ethereal suggestion will be much help. Or will it? (This is why I have been providing ssldumps instead of tcpdumps.)
Thanks,
Donnie
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  #17  
Old 2006-12-03, 23:45
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luz luz is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Quote:
Since the problem only occurs on HTTPS requests, I don't think the wireshark/ethereal suggestion will be much help.
Of course you are right - I just forgot about SSL when I proposed this.

What might help is using the DBG client. It will log some more information about sending and receiving data (after it passed the SSL stack in the client) that might reveal something.
Just HotSync once after the failing session and pick the sysynclog_*.PDB files from the HotSync backup folder on the PC.
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  #18  
Old 2006-12-05, 01:47
dwoodruff dwoodruff is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

I tried Softick PPP as suggested and the same problem occurs when sync'ing a contact when 10000 bytes in the comment field. (I have 10000 z's in the comment field.)

I've attached the following:
ssldump.bad_local
sysynclog*.txt

The sysynclog_palm_session.txt reports:
WARNING: Aborting Session with Reason Status 20006 (LOCAL problem) ***
The Synthesis client reports "No SyncML response".

Could this be the problem?

As always, thanks for your help!
Donnie
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File Type: zip local_test.zip (29.2 KB, 2 views)
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  #19  
Old 2006-12-06, 10:42
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luz luz is offline
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Exclamation Re: https problem with OX and 2.9.9.8 (Palm DBG)

Thanks for the logs.

Now, comparing the SSL dump and the client logs, I guess I found the problem. It seems to be a bug in the SyncML toolkit HTTP code (xpt), but it needs a special condition to cause any harm: When the server sends some raw data that does not decode into any net output (HTTP) data, the HTTP stack treated this as an end of document.
Apparently exactly this happens with the OX server - the chunk header is sent separate from the data block and of course does not translate into any net output by itself:

Code:
    ---------------------------------------------------------------
3 18 1164927004.5341 (0.0022)  S>CV3.0(22)  application_data
    ---------------------------------------------------------------
    1ff8
    ---------------------------------------------------------------
3 19 1164927004.5386 (0.0045)  S>CV3.0(4112)  application_data
    ---------------------------------------------------------------
    02 00 00 6a 1d 2d 2f 2f 53 59 4e 43 4d 4c 2f 2f    ...j.-//SYNCML//
    44 54 44 20 53 79 6e 63 4d 4c 20 31 2e 31 2f 2f    DTD SyncML 1.1//
    45 4e 6d 6c 71 03 31 2e 31 00 01 72 03 53 79 6e    ENmlq.1.1..r.Syn
    63 4d 4c 2f 31 2e 31 00 01 65 03 31 37 00 01 5b   cML/1.1..e.17..[
The "1ff8" is the chunk header.
I fixed this and built a new DBG version of the client (download here). Could you please check if it now works ok? Because I can't really test it as our server does not separate the chunk header this way.

BTW: While looking through the ssldump, I found some other interesting detail:
Code:
3 13 1164926999.6933 (1.6868)  S>CV3.0(242)  application_data
    ---------------------------------------------------------------
    HTTP/1.1 200 OK
    Date: Thu, 30 Nov 2006 22:49:57 GMT
    Server: Apache/2.0.49 (Linux/SuSE)
    Connection: Keep-Alive, Keep-Alive
    Content-Length: 618
    Keep-Alive: timeout=15, max=100
    Content-Type: application/vnd.syncml+wbxml
What's the reason for this duplicate "Keep-Alive"?
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  #20  
Old 2006-12-06, 12:55
dwoodruff dwoodruff is offline
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Default Re: https problem with OX and 2.9.9.8 (Palm DBG)

Lukas,

Initial sync of this new version (3.0.0.1) worked! I'll do some testing today and let you know if I run into any other problems.

I'll see that the OX developer reads this posting.

THANKS and I'll keep you posted on our testing.

Donnie
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